Thread or the like



Aug. 6, 19 91 H. B. KLlN E ET AL THREAD OR THE LIKE Filed 001:. 26, 1936 3 Sheets-Sheet 1 W Y M J W m? m N 0mm E W N [ER E J M, 2 Z M n I g- 6, 1940. H. B. KLlNE ET AL 2,209,983

THREAD OR THE LIKE Filed Oct. 26, 1936 s Sheets-Sheet 2 v INVENTORS HAYDEN B- KLINE LAVERN J.JORDAN A TTORNEY g- ,1 H. B. KLJNE ET AL 2,20 83 THREAD OR THE LIKE Filed Oct. 26, 1936 SSheets-Sheet 5 2o 40. so so 1oo 120 14c 166 180 200 220 240 260 280 300 WEIGHT-0F Mo/srans M/ THREAD MOISTURE CONE/W" WEIGHT 0F some any THR540 INVL'NTORS W HAYDEN B. KLINE L/EVERN J.JORDAN F5012 W 1 ATTORNEY Patented Aug. 6, 1940 UNITED STATES 2,209,983 7 THREAD on THE LIKE Hayden B. Kline, Cleveland, and Lavem J. Jordan, Fairview, Ohio, assignors to Industrial Rayon Corporation, Cleveland, Ohio, at corporation of Delaware Application October 26, 1936, Serial No. 107,668 r 3 Claims.

This invention relates to viscose artificial silk thread having highly uniform physical and physicochemical properties. More particularly, it relates to viscose artificial silk thread having. along 5 its entire length a highly uniform, determinable residual capacity to shrink, preferably of small magnitude. The term residual capacity to shrink may be defined as the amount, in proportion to its original dry length, by which thread will, if unrestrained, shrink in length upon being rewet and redried. Residual capacity to shrink is imparted to thread when it is prevented from completely shrinking while being dried, the amount of shrinkage which the thread is permitted before being prevented from further shrinkage determining the residual capacity to shrink imparted to the thread.

A convenient laboratory method of determining such residual capacity to shrink involves suspending a convenient length of the dry thread,

say 100 cm., in a vertical glass tube which serves to protect the thread from outside conditions.

A suitable weight, of the magnitude of 1 gram for each 150 denier of titre of the thread, is attached to the lower end of the thread to overcome any inherent tendency of the thread to crinkle or curl, which, if it were permitted, would diminish the accuracy of the test. Since this weight is slight in proportion to the denier of the thread being tested, it does not unduly stretch the thread. The length of the dry thread is then noted, after which the thread is thoroughly wet by water which is passed into the tube.

The length to which the thread stretches while wet may then be noted, after which the thread is dried, as by passing heated air through the tube, to substantially the moisture content which the thread possessed in its initially dry condition. If the thread being tested has a residual capacity to shrink, it will be evidenced by the fact that the length to which the thread shrinks upon being redried is less than its original dry length, the amount of thread shrinkage, in proportion to the original length of the dry thread, being the residual capacity of the thread to shrink.

All figures hereinafter quoted for residual shrinkage have been obtained according to this method.

A uniform determinable low residual capacity to shrink, as well as uniformity of other physical and chemical characteristics, is particularly desirable in thread employed in the weaving of fabrics. In the manufacture of such fabrics, the cloth is initially woven to a width substantially equal to or somewhat'greater than the width of the finished fabric. In the finishing operations,

the woven fabric, after being washed, dyed, etc., is dried in tentering frames which hold the fabric to the desired finished width. Since the looms on which the fabric is wovemare of fixed widths, the width to which the fabric is initially woven 5 may not conveniently be changed to compensate for high residual shrinkage of the thread. If the thread of which the fabric is formed has a high residual capacity to shrink, tearing of the fabric may result during the drying operation due to stresses set up in the fabric as it shrinks while being held in the tentering frames. For this reason, it is desirable that the thread forming the fabric have a low residual capacity to shrink. g

Thus, in the'case of fabric woven of viscose artificial silk thread manufactured to the finished width and dried on tentering frames on which it is-held to the finished width, it has been found that if the residual capacity to shrink of the viscose artificial silk thread is substantially more than about 2.5%, tearing of the cloth will rsult due to stresses set up therein by shrinkage of the thread. It has been found, however, that in the case of viscose artificial silk thread, the most satisfactory results are obtained when the thread hasa residual capacity to shrink which does not exceed 1.0%. The residual capacity to shrink may, however, advantageously be considerably less, while nevertheless determinable, than the latter value.

Non-uniformity in the shrinkage or other physical characteristics of the thread causes imperfections to appear in finished fabrics, which imperfections are especially noticeable in dyed fabrics of woven construction. Therefore, a high degree of uniformity of physical and chemical characteristics of the thread, and particularly a uniform residual capacity to shrink of the thread, is desirable for the manufacture of woven fabrics. This is especially in the case of fabrics woven from viscose artificial silk thread, sincev variations in the residual capacity to shrink ofsuch thread markedly affect the uniformity with which the fabric may be dyed. The manner of drying viscose artificial silk thread determines to a large extent the uniformity and amount of residual capacity to shrink imparted to the thread, as well as the uniformity of other physical andphysico-chemical characteristics of the thread.

For instance, itis diflicult to form satisfactory Woven fabrics of artificial silk thread, particularly viscose thread, which has been produced by the spool-spinning process, in which, in conventional practice, the thread is dried while wound on the spool on which it has been collected. Such thread does not possess a satisfactory degree of uniformity of physical characteristics, particularly in respect of residual capacity to shrink. This arises from the fact that the thread does not shrink uniformly when dried on the spool, as a result of which the residual capacity of the thread to shrink varies widely at different points along its length. For instance, portions of the thread which are prevented from shrinking while drying, such as portions which are wound directly on the spool and portions on the outer surface of the cake of thread which dry more rapidly than the inner portions of the cake, have a high residual capacity to shrink. Upon rewetting, they may, in the case of viscose thread, shrink to an extent greater than l of their original dry length. Other portions of the thread which are permitted to shrink more or less freely, such as portions of thread in the inner layers of the cake, have a relatively low residual capacity to shrink.

Tests performed according to the above-indicated method show that, in a single viscose thread dried on a spool, the maximum residual capacity of the thread to shrink is, as a general rule, about ten times as great as the lowest residual capacity to shrink. It is, however, sometimes as much as twenty times the lowest residual capacity to shrink. If such spool-dried thread is woven into a fabric which is dried in a tentering frame,

the fabric will not shrink uniformly due to such varying residual capacities to shrink. This nonuniform shrinkage will cause barr effects in the fabric, which are especially noticeable when the fabric is dyed. As an example, the portions of thread of high residual capacity to shrink are under much greater tension, due to shrinkage, than are other portions of the thread when the fabric is dried. They thus form bright streaks in the cloth known to the trade as shiners.

With a view to minimizing the defects arising from spool-drying of thread, most of the artifi- -cial silk thread manufactured for the weaving industry by wet-spinning processes is produced by the comparatively more expensive pot-spinning system, in which the thread is unwound from the pot-spun cakes and reeled while wet into skein form. In such form, it is dried while hanging loosely, thus permitting substantially free and unrestrained shrinkage of the thread. Thread so dried, when tested as outlined above, does not show a residual capacity to shrink; in fact, upon being rewet and redried according to the above test, the skein-dried thread is found to be actually longer than its original dry length. Thread so dried while in skein form, furthermore, does not have physical and chemical properties which areas uniform as might be desired. This may be due to the fact that, due to the weight of the thread, the tension in various portions of the thread varies, or to the fact that the thread inside the skein winding dries at a different rate than that outsidethe skein winding, or for other reasons which may depend on the kind of artificial silk thread produced.

Thus in the case of viscose artificial silk thread, uniformity in the physical and chemical characteristics of the thread is ordinarily diflicult to obtain because of the large number of processing steps, such as coagulation, washing, desulphurizing, bleaching, drying, etc., which are required to produce finished viscose thread. Variations in any of the processing steps may be reflected as variations in the characteristics of the finished thread. A high degree of uniformity of the charprocessing treatment to which each batch is subjected, as well as variations in identical processing treatments performed on different batches. Such variations, of course, are in addition to the above-indicated variations occurring in the drying of spool-spun or pot-spun thread.

However, in continuous processes of manufacturing thread in which a plurality of threads are subjected to processing treatment, it is possible to obtain an extremely high degree of uniformity of characteristics of the thread, since all portions of all threads are subjected to identical processing treatments. Therefore, continuously processed thread may reach the drying stage with a very high degree of uniformity in thread characteristics, which uniformity may be maintained, or even improved, by uniform drying. Methods and apparatus by means of which may be produced the high grade product of the present invention are described hereinafter, according to which methods and apparatus the desired processing treatments are applied to the thread continuously with its formation. The thread is continuously dried in a manner which permits unrestrained shrinkage of the thread to a point at which the desired residual capacity to shrink is imparted to the thread. i

The present invention, therefore, provides viscose artificial silk thread or the like having physical and physico-chemical characteristics of an exceptionally high degree of uniformity along its entire length and particularly possessing a determinable residual capacity to shrink which is highly-uniform along the entire length of the thread.

The thread of the present invention may be produced on apparatus such as that shown in the drawings, in which Figure 1 is a side elevation, along line l-l of Figure 2, of a machine for the continuous production of artificial silk thread. Figure 2 is a portion of the front elevation of the machine from line 2-2 of Figure 1. Figure 3 is a detail elevation on a larger scale of a portion of the machine, parts being in section, particularly showing means for drying the thread. Figure 4 is a front elevation of the portion of the machine shown in Figure 3. Figure 5 is an elevation to an enlarged scale of a form of winding reel on which the thread may be dried, parts being broken away to more clearly show the construction thereof. Figure 6 is an end elevation of the reel of Figure 5 from line 6-6 of Figure 5. Figure '7 is a typical graph showing the amount of shrinkage ofv a specimen of viscose artificial silk thread upon a reduction in its moisture content. Figure 8 is a diagrammatic representation of the profile contour of a reel based upon the graph of Figure '7. Figure 9 is a diagrammatic comparison of a preferred profile contour for a reel with the profile contour of Figure 8. Figure 10 is a diagrammatic representation of the relationbetween a reel having the preferred profile contour of Figure 9 and a thread passing thereover. Figure 11 is a representation of portions of several threads of the present invention, while Figure 12 is a representation of portions of several ordinary skein-dried threads.

In the drawings, like reference characters refer to like parts throughout.

The apparatus illustrated in Figures 1 and 2 is of the same general type as that shown, described, and claimed in copending application Serial No. 1,114, filed February 18, 1936. It is comprised of a plurality of threadproducing units disposed at intervals lengthwise of the apparatus in each of which units the thread I is produced by extrusion of viscose from spinneret 2 into a coagulating bath 3 contained in trough 4. The thread is withdrawn from the bath 3 by means of a reel 5 on which, during rotation thereof, the thread is wound and advanced axially thereof in a plurality of spaced generally helical turns. The thread proceeds downward through channel 6, disposed at the working edge of the trough, to the first of a series of reels-which, in the drawings, bear reference numerals 1 to i5, inclusive, on each of which, during rotation thereof, the thread is stored in a plurality of spaced generally helical turns which are advanced axially of the reel. After. leaving the drying reel l5, the thread passes to a suitable collecting means such as cap-twister l6.

While the thread is stored on each of .the reels 1 to 15, inclusive, one or more processing treatments may be applied thereto. Thus, in the illustrated apparatus, liquid processing treatments, such as desulphurizing, washing, bleaching, etc., may be applied to the thread on reels 1 to 13, inclusive. The processing liquid applied to the thread on each of said reels is supplied from a suitable reagent distributor l1 supplied from a pipe I8 extending longitudinally of the machine and serving corresponding reels in a horizontal series. The liquid is collected in a trough l9 below the reels, each of which troughs extends longitudinally of the machine and serves corresponding reels in a horizontal series. On reel 14 the thread may be stored thereon to allow excess liquid to drip off before it is passed to drying reel l5.

The number of reels on which the thread may be processed may be either more or less than that shown, depending upon the number and kind of processing treatments which it is desired to apply to the thread.

The reels may be of cantilever form as illustrated, being supported from one end only and having the other end free and unobstructed, which permits them to be disposed in the stepped arrangement illustrated: such an arrangement is advantageous in that it provides ready access to the reels for threading up, ment, repair, etc. This is true even though a great many thread-producing units are disposed in side-by-side relation lengthwise of the machine as a whole. If desired, each of the reels in each vertical series may be driven through gears 2| and 22 from a drive shaft 23, which is driven by a shaft 24 which extends longitudinally of the machine and drives the drive shafts 23 for the vertical series of reels.

Cap-twister l6 may be actuated in any suitable manner: in the apparatus illustrated, a belt 25 driven by a drum 26 rapidly rotates the bobbinsupporting whirls 21 for a pair of adjacent cap' twisters while they are being vertically reciprocated by chain 28 which is actuated through lever 29 from cam 30. I

As has been indicated, the manner of drying inspection, replacediiferent portions of its length when the thread is dried while wound on spools or in skein form are obviated when the thread is dried on such a reel, since only a single layer of thread is exposed to drying and since each increment of thread passing over the reel is subjected to identicaldrying conditions, which factors result in highly uniform drying of the thread. An example of one form of reel adapted to the production of the thread of the present invention is illustrated in Figures 5 and 6.

The reel of Figures 5 and 6, which may corre- I spend to reel I5 of the apparatus of Figures 1 and 2, is of a type generally similar to the reel shown, described, and claimed in application Serial No. 652,089, entitled Winding reel, filed January 16, 1933 by Walter F. Knebusch. From these figures it can be seen that each reel comprises two rigid, generally cylindrical members 32 and 33. Member 32, which may be termed the concentric member, is mounted concentrically upon and for rotation with drive shaft 34 and has its periphery comprised of a plurality of bar members 35. Member 33, which may be termed the eccentric member, is rotatably mounted with its axis slightly offset from and askew to that of member 32 and has its periphery comprised ofa plurality of bar members 36 equal in number to the bar members and alternately disposed therewith.

Concentric member 32 may be formed as shown, having the bar members 35 formed on the periphery of a cylindrical body 31 in which case great rigidity is imparted to the bar members 35. While member 32 may be mounted on the drive shaft 34 in various manners, in that shown the generally cylindrical body 31 thereof is provided with slots 38 at the inner end, in which slots are disposed the ends of pin 39 mounted in drive shaft 34 against which pin 39 cylindrical body 31 is held by cap nut 4| which is threaded into the. end of drive shaft 34. Concentric member 32 is thus caused to rotate with shaft 34 by means of pin 39.

Eccentric member 33 is formed of a rigid cagelike member 42 mounted concentricallyupon an annular supporting member 43 by bolts 44. Rigid cage-like member 42 is formed of the aforesaid bar members 36 which are provided at their free ends with an internal annular reinforcing rib 45 and at their supported ends with an external annular supporting rib 46 by means of which the cage-like member 42 is mounted on annular supporting member 43. Annular supporting member 43 is rotatably supported on frame member 41 in the desired oiTset and askew position with respectto the axes of concentric member 33, the

shaft 34 being journalled "or otherwise supported in correct relationship withframe member 41.

Rotation of reel drive shaft 34 causes concentric member 32 fixed thereto to rotate, whereupon contact of bar members 35 of concentric member 32 with bar members 36 of eccentric member 33 causes said eccentric member to rotate at the same angular speed. During such rotation, the offset rotation of the generally cylindrical members 32 and 33 causes the thread to transfer from the bar members of one generally cylindrical member to the bar members of the other generally cylindrical member. At the same time, the askew relationship of the generally cylindrical members causes the thread to advance in a plurality of spaced generally helical turns lengthwise of the reel. In the employment of cantilever reels, of which the one discussed is an example, it has been found desirable to advance the thread from the supported end of the reel to the free end thereof, in which case access to the reel, as for starting of thread on the reel, etc., is greatly facilitated. The other reels 5 and I to I4 inclusive, may be of the same general type and operate in the same general manner.

As the thread is continuously stored on the drying reel of Figures 1 and 2, it may be dried by suitable means. As shown in Figures 3 and 4, the drying may be accomplished by means of heated air supplied from a supply manifold 50 to hollow shaft 3d of the reel I5. The heated air pases through the holes 5| in shaft 34 (Figure 5) to a chamber 52 in the interior of tlie cylindrical body 37 of concentric member 32, and reaches the thread stored on the reel through holes 53 in the wall of cylindrical body 31, which holes may extend toward the spaces between the bars 35 of concentric member 32.

To aid in the drying of the thread by providing better control over the drying operation, as well as to conserve the air, a suitable housing 54 may be provided to surround the drying reel 15, said housing being furnished, if desired, with a door 55 by means of which access may be obtained to the reel l5 for threading up, inspection, repair, etc. The air may pass from housing 54 through return duct 56 to an exhaust manifold 51 from whence it may pass to suitable reconditioning or reheating means, not shown, after which it may be recirculated back to supply manifold 50.

If the reel is made of metal having good heat conductivity, drying of the thread may be caused to a material extent by conduction of the heat through the reel members to the thread as well as by convection of the air.

In the reel illustrated in Figures 5 and 6, provision is made for allowing substantially unrestrained shrinkage of the thread I to a point at which the thread has the desired residual capacity to shrink. This is accomplished while the thread is being progressed lengthwise of the reel in a plurality of spaced, generally. helical turns. This can be done, as in the illustrated reel, by providing a periphery of suitable form. In general, such periphery is made up of two substantially cylindrical portions separated by a frustoconical portion, as will appear.

To aid in understanding the function of the reel in permitting substantially free or unrestrained shrinkage of the thread, a typical shrinkage curve for one kind of viscose thread has been reproduced in Figure 7. The curve of Figure 7 represents the percentages of unrestrained shrinkage of the thread from the wet condition for various percentages of moisture in the thread. The moisture content, plotted as the abscissa, is the proportion that the weight of the moisture in the thread bears to the weight of the bone dry thread at any given time, while the percentage of shrinkage, plotted as the orlength of the thread due to shrinkage bears, for a given moisture content, to the original wet length of the thread.

As can be seen from this curve, as the moisture content of the thread is reduced by drying, as from 300% to approximately very little shrinkage of the thread occurs. However, on the curve of Figure 7, at a moisture content of approximately 150%, noted as point B on the curve, pronounced shrinkage of the thread begins, which increases as the moisture content of the thread is reduced. When the moisture content of the thread is reduced to zero, the particular thread for which the curve of Figure 7 was determined, if not restrained against shrinking, shrinks somewhat more than 6% of its original length.

The occurrence of but slight shrinkage of the thread while its moisture content is being reduced from 300% to 150% may be due to the fact that substantially all of the moisture removed from the thread during this drying phase may be surface moisture, while the high percentage of shrinkage which occurs while the moisture content of the thread is reduced from 150% is probably due to a change in the structure of the thread during the removal of internal moisture from the thread. It has been found that the moisture is rapidly removed from the thread until its moisture content is reduced to the point of pronounced shrinkage, whereas the remaining moisture is removed from the thread more slowly. This is probably due-to the fact that the surface moisture is rapidly removed by evaporation, while the remaining moisture in the thread is removed more slowly by diffusion.

A theoretical contour for the bars of a reel of the type described may be constructed which will allow for a reduction in the moisture content of a given kind of thread under a given set of operating conditions.

Such a contour is represented by the profile of Figure 8. From the point a to point I) of Figure 8, the moisture content of the thread may be reduced to the condition represented by B in Figure '7. The radial dimension of the substantially circular reel illustrated at point b is but slightly smaller than the radial dimension of the reel at point a because of the small shrinkage which the thread would undergo while having its moisture content reduced to the condition represented at B. The radial dimension at point 0 would correspond to the total amount of shrinkage which the thread undergoes in reaching a zero moisture content. Between the points b and c the contour of the reel would, for a certain set of operating conditions of the reel, be determined by the portion of the curve of Figure '7 to the left of point B. The portion of the reel between points 0 and d may have the same radial dimension, since the thread has completed its shrinkage when it reaches point c.

It will be observed that the linear distance between points a and b is less than the distance between points I) and 0 because, as has been noted, surface moisture is rapidly being removedbetween a and b, whereas internal moisture is being removed between points b and c.

A reel having the profile contour represented by Figure 8 would, however, dry the thread in the desired manner only. under the set of operating conditions upon which the contour is based. This would include the temperature and humidity of the air supplied, the speed of rotation,

dinate, is the proportion that the reduction in size and material of the reel used, the pitch 7 of the thread turns being advanced along the reel, as well as the size and kind of thread being dried. For any variation of these conditions, changes in the conformation of the reel shown in Figure 8 would be required. Due to the difficulty of maintaining uniform operating conditions in practice, the contour of a preferred reel preferably varies as hereinafter described from the contour of Figure 8. A further variation in the contour of such a, preferred reel from that represented by Figure 8 is called for when it is desirable to produce a finished thread having a residual capacity to shrink.

, by the relation between the heavy line and the broken line.

From point A and B on the solid line, the preferred reel is cylindrical. This variation from the non-cylindrical portion between a and b in Figure 8 is of no importance as it is too' slight to affect the quality of the finished thread. From B to C in Figure 9 the heavy line lies inwardly of the corresponding part of the broken line. From point C to D, the preferred reel is preferably of cylindrical forma tion and of larger diameter than the diameter of the theoretical reel between points cd. The preferred reel between points CD may be larger than the theoretical reel between c-d in order to produce a thread having a residual capacity to shrink. The intersection between the con-. tour of a theoretical reel and the contour of a preferred reel based on the same operating conditions is at E in Figure 9.

In operation, as the thread is advanced lengthwise of the reel in a plurality of generally helical turns, it will, in passing from A to B, have its moisture content removed to the point indicated by B in Figure 7, at which pronounced shrinkage begins to occur. After leaving B. the thread shrinks, but inasmuch as the diameters of this portion of the reel decrease somewhat more rapidly than do the diameters of the thread turns in consequence of shrinkage of the thread,

the latter will contact only loosely with the reel.

It will not contact firmly therewith until the point E is reached. This phenomenon is illustrated in Figure 10, from which it will be seen that between B and E the thread appears to stand off the reel. Since the thread, in advancing between points B and E, is loosely supported on the reel, unrestrained shrinkage of the thread may therefore take place over this portion of the reel until the thread contacts the portion CD of the reel at point E. The shrinkage of the thread is therefore halted when the turns thereof contact portion CD of the reel at point E, although drying of the thread proceeds as it advances along portion CD of the reel.

Thus a predetermined residual capacity to shrink may be imparted to the thread, since the unrestrained shrinkage of the thread is halted after it has proceeded to the desired point.

By varying the size of portion CD of the reel, it is apparent that the residual capacity to shrink of the thread may be varied. For instance, by decreasing the diameter of the generally cylindrical portion CD of the reel, the residual capacity to shrink may be decreased; indeed, by

making the portion CD of the reel of suitable size, thread may be produced which may have a determinable residual capacity to shrink which is very close to, if not actually, zero. By increasing the diameter of said generally cylindrical portion CD, the residual capacity to shrink may be increased. The length of portion CD of the reel may be somewhat longer than that actually required to dry the thread to the desired moisture content, this in order to provide a period for the thread to reach equilibrium drying conditions before it leaves the reel. It may be desirable not to completely dry the thread on the reel, but to dry it to a condition in which it has a moisture content of the order of 10%, corresponding to the regain moisture content of thread produced by ordinary methods. A moisture content of this magnitude is desirable if "-te thread is twisted,

since it aids in the twisting operation.

It has been found that the amount of tension in the thread at the beginning of the drying operation appreciably affects the amount of residual capacity to shrink imparted to the thread when dried on a reel as outlined above. Thus, if the initial tension in the thread is high, a higher residual capacity to shrink will be imparted to the thread than otherwise. Therefore, to reduce or eliminate the tension in the thread, it has been found desirable to provide a peripheral speed of the portion of the drying reel on which thread first starts; i. e., portion A-B of the illustrated reel, which is lower by a suitable amount than the peripheral speed of the discharge end of the preceding reel. This may be accomplished by rotating the drying reel and the preceding reel at different speeds or by making the diameter of portion A-B of the drying reel less than that of the discharge end of the preceding reel and driving both reels at the same speed or by a combination of these methods.

Variations within reasonable limits of the operating and/or drying conditions of the reel will not affect the residual capacity to shrink of thread dried on a reel of the preferred form. Such variations will increase or decrease the rate of drying of the thread and, in the illustrated reel, will merely vary the position of the point E longitudinally of portion CD of the reel. The thread is still permitted unrestrained shrinkage until it reaches the smaller generally clyindrical portion CD of the reel. .Because of the fact that the conditions under which thread may be dried on reels having contours of the above type may vary within reasonable limits without appreciable variations in the physical properties of the thread, it is therefore possible to simultaneously dry a plurality of difierent threads without having an appreciable variation from thread to thread in the residual capacities to shrink thereof, as well- ".5 in other physical and chemical characteristics which might be affected by variations in drying conditions. This is particularly advantageous since, in the operation of machines in which large numbers of thread are dried, it is not commercially practicable to have identical drying conditions for all threads, due to the diificulty of maintaining such conditions.

The above-described contour of the drying reel is shown, described and claimed in a copending application Serial No. 107,667 filed in the'names of Hayden B. Kline and Lavern J. Jordan.

' As an illustrative example of the operation of a reel having a contour of the type shown in Figure 8, it has been found inactual practice that desirable results are obtained in drying 150 denier 40 filament viscose artificial silk thread on an aluminum drying reel of the type illustrated in Figures and 6. In such a reel, the diameters of the reel members at portions A-B thereof may be 4.950"; the diameters of the reel members at portion C-D thereof, 4.700"; the distance from point A at which the thread starts on a reel to point B, and the distance from point B to point C, 1 The reel is preferably rotated at 165 R, P. M., the thread being supplied from a preceding drip reel rotating at the same angular speed and having reel members of 5" diameters at their discharge ends. The thread, due to the construction of the reel is advanced in a plurality of advancing helical turns which are spaced approximately A of an inch apart. It may be dried by heated air supplied at about 185 F. at a static pressure of about 6" of water.

Tests made at intervals along the lengths of each of a number of threads produced on a machine of the type described, the same having been dried on reels of the indicated dimensions operating under the indicated conditions, reveal that the residual capacity to shrink of each such thread is at all points less than 1.0%. The average residual capacity to shrink of each thread is in the neighborhood of 0.6%, with a maximum variation therefrom, plus or minus, not greatly in excess of about 0.3%. The difference between the maximum and minimum residual capacities to shrink of all threads, taken together, is substantially less than 0.8%, but in no case does the difference between maximum and minimum capacities to shink of any given thread exceed 0.6%. All other physical and chemical characteristics of the thread are likewise extremely uniform,

Moreover, the thread of the present invention; i. e., thread dried in the manner outlined above, is characterized even when free of tension by an uncrinkled appearance, whereas skein-dried thread likewise free of tension before it is Wound presents a wavy, crinkled appearance along its entire length.

The two types of thread may be compared by referring to Figures 11 and 12, which are fullsized representations of actual specimens of viscose artificial silk thread. Figure 11 represents several threads of the present invention: the threads thereof are extremely straight and wholly uncrinkled, undoubtedly due partly to the fact that the thread is produced by a continuous proc ess which results in extremely uniform processing of all portions of the thread and partly to the continuous, uniform drying of the thread. Figure 12 represents several threads produced by one of the conventional non-continuous processes, the same having been dried in skein form: the wavy, crinkled conformation characteristic of such thread may be due to any one or to a combination of the several factors hereinafter mentioned.

The -crinkled conformation of skein dried thread probably results directly from the step of drying the thread in skein form. When the thread is dried in skein form, different portions of the thread may dry at difierent rates and, as a result, certain filaments may be caused to shrink more or less than other filaments in the same portion of the thread. Consequently, the portions of the filaments which have shrunk more than other filaments may draw up such other filaments, forming waves or crinkles in such thread. Such tendency of certain filaments in the same thread to shrink more than others may also be. due to the fact that when thread is manufactured according to conventional non-continuous processes it is possible that certain filaments may be given more or less intensive processing treatment than other filaments, thus imparting different tendencies to shrink to different filaments in the same thread. Another factor which may play a large part in causing the wavy or crinkled appearance of such thread lies in the fact that the thread is subjected to liquid processing treatment while in skein form: the shower of liquid may cause undulations to form in the thread which may remain in and become set in the thread upon drying.

Due to the crinkled conformation of ordinary skein-dried thread, the filaments thereof tend to spread. The thread of the present invention, on the other hand, is very compact, all of the filaments lying closely together. Therefore, the thread of the present invention may be unwound more readily from the package in which it is collected than skein-dried thread, since there is less possibility of entangling, with a consequent breakage, of the filaments. Furthermore, the thread of the present invention may be more readily formed into woven fabrics than can skein-dried thread, since in the weaving operation there is less possibility of broken threads or filaments with the uncrinkled, compact thread of the present invention than with skein-dried thread the filaments of which are separated from each other. The thread of the present invention is therefore much more uniform and of a higher quality than any heretofore available for weaving purposes.

It is apparent that the apparatus shown and described for the production of the thread of the present invention, while wholly practicable, is purely illustrative. Various other forms of apparatus may be used in lieu thereof without in any way departing from the spirit of the invention. In the appended claims, the term thread is intended to include, besides thread, such thread-like materials as filaments, artificial horsehair, staple fiber, artificial ribbon and like materials. It is intended that the patent shall cover, by suitable expression in the appended claims, whatever features of patentable novelty reside in the invention.

What is claimed is:

1. Bleached, desulphured multiple filament viscose artificial silk thread which has a residual capacity to shrink measured according to the system hereinabove described which, while not at any point exceeding 1%, does not deviate either way from its average residual capacity to shrink by more than about 0.3%, which has extremely uniform physical and physico-chemical characteristics throughout its length, which when wound in package form is free from variations in such characteristics from one end to the other of the same thread, which is free from the periodic denier variations inherent in discontinuously produced thread as a result of reciprocation of the guide conventionally employed to lay the plastic thread in package form, which immediately after completion of the drying operation presents a straight, uncrinkled appearance even when free of tension, and which when dyed in the piece is characterized by extreme levelness of dyeing.

2. Bleached, desulphured multiple filament viscose artificial silk thread which has a residual capacity to shrink measured according to the system hereinabove described which, while on the average of the order of 0.6%, does not deviate either way from its average residual capacity to shrink by more than about 0.3%, which has excharacteristics throughout its length, which when wound in package form-is free from variations in such characteristics from one end to the other of the same thread, which is free from the periodic denier variations inherent in discontinuously produced thread as a result of reciprocation of the guide conventionally employed to lay the plastic thread in package form, which immediately after completion of the drying operation presents a straight, uncrinkled appearance even when free of tension, and which when dyed in the piece is characterized by extreme levelness of dyeing.

3. Bleached, desulphured multiple filament viscose artificial silk thread which has a residual capacity to shrink measured according to the system hereinabove described which, while on the'average of the order of a fraction of 1%, doesnot deviate either way from its average residual capacity to shrink by more than about 0.3%,

dyed in the piece is characterized by extreme levl5 elness of dyeing.

HAYDEN B. KLINE. LAVERN J. JORDAN. 

